Marine organisms as a source of novel lead structures for drug development

Screening of extracts obtained from terrestrial plants and animals has yielded a large number of novel natural products. Many of these have been developed into useful, medicinal agents either directly as the natural product or through synthetic modification. It has been estimated that for the period 1983-1994, 78% of the antibacterial agents and 61% of the 31 anticancer agents approved for use, were derived from terrestrial natural products. By comparison the marine environment remains relatively unexplored. The oceans cover over 70% of the Earth's surface. Estimates of the number of marine invertebrate and algal species are at least 200,000, while those for marine microbial strains range into the millions.